The use of face masks and other personal protective equipment (PPE) such as surgical gowns, surgical drapes, bouffant caps, etc. is a recommended practice in the healthcare industry to help prevent the spread of disease. For instance, face masks worn by healthcare providers help reduce infections in patients by filtering the air exhaled from the wearer thus reducing the number of harmful organisms or other contaminants released into the environment.
This is especially important during surgeries where the patient is much more susceptible to infection due to the presence of an open wound site. Similarly, patients with respiratory infections may use face masks to prevent the spread of disease by filtering and containing any expelled germs. Additionally, face masks protect the healthcare worker by filtering airborne contaminants and microorganisms from the inhaled air.
Some diseases, such as hepatitis and AIDS, can be spread through contact of infected blood or other body fluids to another person's mucous membranes (i.e., eyes, nose, mouth, etc.). The healthcare industry recommends specific practices to reduce the likelihood of contact with contaminated body fluids. One such practice is to use face masks, surgical gowns, surgical drapes, bouffant caps, and other similar PPE, which are resistant to penetration from a splash of body fluids.
The material used to form such PPE can be comprised of several layers. The layer that is positioned closest to the skin of the wearer is typically referred to as the inner layer. The layer furthest from the skin of the wearer is referred to as the outer layer. An additional layer or layers of material can be disposed between the outer layer and the inner layer. Typically, one of these additional layers is a filtration layer, such as a microfiber fiberglass layer or an electret-treated meltblown layer.
As stated, face masks, surgical gowns, surgical drapes, bouffant caps, and other similar PPE may be designed to be resistant to penetration by splashes of fluids so that pathogens found in blood or other fluids are not able to be transferred to skin of the user of such PPE. The American Society of Testing and Materials (ASTM) has developed test method F1862-13, “Standard Test Method of Resistance of Medical Face Masks to Penetration by Synthetic Blood (Horizontal Projection of Fixed Volume at a Known Velocity” (2013) to assess an article's ability to resist penetration by a splash at three levels of pressure. This method is referenced in ASTM F2100-11, “Standard Specification for Performance of Materials Used in Medical Face Masks” (2011), which specifies a set of performance criteria for medical face masks. To achieve Level 3 performance, which is the most stringent level of testing in ASTM F2100-11, a face mask must resist splashes of 2 milliliters of synthetic blood (available from Johnson, Moen & Co., 2505 Northridge Lane NE, Rochester, Minn. 55906) at 160 mmHg per the ASTM F1862-13 procedure.
The splash resistance of an article of PPE (e.g., a face mask, etc.) is typically a function of the ability of the layer or layers of the structure used in the article to resist fluid penetration, and/or their ability to reduce the transfer of the energy of the fluid splash to subsequent layers, and/or their ability to absorb the energy of the splash. Typical approaches to improving splash resistance are to use thicker materials or additional layers in the construction of the structure. However, these solutions may increase the cost of the structure, increase the weight of the structure, reduce the porosity of the structure, and add discomfort to the wearer by negatively impacting the thermal resistance of the multi-layered structure.
An additional approach to improving the splash resistance of materials or structures used to form face masks, surgical gowns, surgical drapes, bouffant caps, or other similar PPE is to incorporate a layer of porous, high loft, fibrous material. This type of material is advantageous in that the layer will absorb or dissipate the energy of the impact of the fluid splash. However, it is often the case that fluid will saturate this high loft material, hence reducing its effectiveness in absorbing the energy of a future fluid splash. Additionally, fluid can be squeezed out of this high loft material and may be transferred through subsequent layers upon compression of the multi-layered structure.
Moreover, incorporating additional layers of material into the mask can increase the amount of heat contained within the mask's microclimate, which can cause discomfort to the wearer. Further, the face is very sensitive to changes in temperature, much more so than other places in the body. The cheeks and lips are extremely sensitive. When a person wears a mask, the microclimate inside the mask increases a few degrees due to trapped heat from the person's breath. Just a few degrees of heat can be very uncomfortable and result in the wearer feeling they mask is unbreathable and can prevent a person from not complying with PPE protocols.
As such, a need exists for a fabric and articles formed therefrom (e.g., face masks) having improved fluid resistance but without imparting discomfort to the user. In particular, a need exists for a mask that can cool the microclimate in the dead space of a face mask while at the same time providing enhanced fluid resistance without having to incorporate high loft layers of material into the mask.